This invention relates to identification of a service provided from a central node in a system wherein multiple data streams are enabled and where the service delivery includes at least one intermediate node.
A communication system is a facility which facilitates communication between two or more entities such as communication devices, network entities and other nodes. A communication system may be provided by one more interconnect networks. One or more gateway nodes may be provided for interconnecting various networks of the system. For example, a gateway node may be provided between an access network and other communication networks, for example a core network and/or a data network. The communication may comprise, for example, communication of data for carrying communications such as voice, electronic mail (email), text message, multimedia and so on.
A user may communicate via a communication system and access various applications by an appropriate communication device. An appropriate access system allows the communication device to access to the communication system. An access to the communications system may be provided by a fixed line or wireless communication interface, or a combination of these. Examples of wireless access systems providing mobility for the users thereof include cellular access networks, various wireless local area networks (WLANs), wireless personal area networks (WPANs), satellite based communication systems and various combinations of these. A communication system typically operates in accordance with a standard and/or a set of specifications and protocols which set out what the various elements of the system are permitted to do and how that should be achieved. For example, it is typically defined if the user, or more precisely user device, is provided with a circuit switched or a packet switched communications, or both. Also, the manner in which communication should be implemented between the user device and the various elements of the communication and their functions and responsibilities are typically defined by a predefined communication protocol. Various functions and features are typically arranged in a hierarchical or layered structure, so called protocol stack, wherein the higher level layers can influence the operation of the lower level functions. In cellular systems a network entity in the form of a base station provides a node for communication with mobile devices in one or more cells or sectors. It is noted that in certain systems a base station is called ‘Node B’. Typically the operation of a base station apparatus and other apparatus of an access system required for the communication is controlled by a particular control entity. The control entity is typically interconnected with other control entities of the particular communication network.
A mobile communication system provides mobility for the users thereof. An example of the third generation (3G) mobile communications systems is the universal mobile telecommunications system (UMTS). A non-limiting example of a possible type of access architecture is a concept known as long term evolution (LTE). A particular example of such systems is the Evolved Universal Terrestrial Radio Access (E-UTRA). An Evolved Universal Terrestrial Radio Access Network (E-UTRAN) includes of E-UTRAN Node Bs (eNBs) which are configured to provide base station and control functionalities. Thus in the UMTS service delivery may include intermediate nodes such as at least one long term evolution (LTE) evolved Node B (eNB).
A service provided for mobile users is multimedia broadcast multicast service (MBMS). The MBMS can be described as a multimedia service that is arranged to transmit MBMS data to users by point-to-point (P-t-P) and/or point-to-multipoint (P-t-M) connections. The multimedia broadcasting multicasting services can be divided in two modes, that is into a broadcast mode and multicast mode. For the operation of the multimedia broadcast multicast service (MBMS) in a system based on the UMTS LTE a technique known as single frequency network (SFN) operation has been proposed. This requires the transmission of identical information, at a transport block level, in each cell of a cell group. Furthermore, the physical layer transmissions in each cell of the group must be synchronised very accurately at both the symbol and frame levels. The technique can be important because a user equipment (UE) receiving MBMS transmissions by SFN methods may obtain significant signal to interference advantages when compared to transmissions made independently in each cell.
To enable SFN operation internet protocol (IP) packets containing the MBMS data to be transmitted is mapped to physical layer transport blocks in an identical manner in each of the eNBs that belong to the SFN group of cells. For radio efficiency this should include the segmentation and concatenation of the IP packets. There are a plurality of ways in which this can be done. One method that has been proposed is for the segmentation and concatenation to take place within the eNB. In order that each eNB maps the same IP packets into the same transport blocks a central node, e.g. an MBMS access gateway, timestamps each IP packet or group of packets. It also needs to attach to each packet the accumulated bytes summed over all previous packets since the first packet to receive a particular timestamp i.e. accumulated bytes since the timestamp changed. The eNBs map the IP packets into the first available resource after the timestamp and continue mapping into successive available resources via segmentation and concatenation until there are no IP packets remaining in the input buffer or a new timestamp is received. The accumulated bytes allow the eNB to re-order the IP packets should they be received out of sequence and detect that they have failed to receive particular packets.